JPH0826235B2 - Method for producing water-soluble dye - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water-soluble dye, and particularly to a method for producing a water-soluble dye having excellent water resistance on a recording paper used as a recording liquid for an inkjet printer or stationery.

[Conventional technology]

Recently, low-impact non-impact printers are increasing as printers in offices. Inkjet printers with low maintenance costs and easy colorization are expected to grow significantly in the future, but the recording liquids used in inkjet printers are mainly water-based from the viewpoint of odor, safety, etc. A water-soluble dye is also used as the dye contained.

On the other hand, also in the field of stationery, oil-based felt-tip pens and the like are changing to water-based due to reasons such as writability, and along with this, the dyes used are also changing to water-soluble dyes.

In any recording liquid, the water-soluble dye used therein is required to have high water resistance on recording paper.

To improve the water resistance of water-soluble dyes on recording paper, increase the number of azo groups in the molecule to polyazo, especially trisazo or more. Reduce the number of sulfonic acid groups in the molecule. Various attempts have been made from the viewpoint of the structure of the iso-dye to be introduced into.

However, such a change in the molecular structure may cause not only the dye itself but also the starting material or amines as intermediates to have a markedly reduced solubility in water and a dilute mineral acid. When the oxidization reaction is carried out by a method involving the action of nitrite in an ordinary dilute mineral acid, not only does the reaction take a significantly long time, but the reaction is often not completed.

Therefore, the yield of the dye obtained by the coupling reaction using the diazotization reaction solution of the amine thus obtained becomes low, and the water resistance is deteriorated due to impurities by-produced during the reaction. As for mutagenicity, problems such as originally negative ones becoming positive have arisen.

[Problems to be solved by the invention]

The present invention has been made to solve the above-mentioned drawbacks, and in order to produce a water-soluble dye having excellent water resistance on a recording paper in a high yield, an excellent diazotization of a poorly water-soluble amine is carried out. It is intended to provide a method.

[Means for solving the problem]

In the present invention, when a water-soluble dye is produced by diazotizing an amine represented by the following general formula [I], [II] or [III] and then reacting it with a coupling component, the diazotization reaction is carried out. The present invention relates to a method for producing a water-soluble dye, which is carried out in an aqueous solution containing 30 to 80% by weight of pyrrolidone or its derivative with respect to the whole medium.

(In the formula, X ¹ , X ² , X ³ , X ⁴ and X ⁵ each represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a lower acylamino group or a sulfonic acid group, X represents a sulfonic acid group, and A,
B and C represent a benzene ring. However, at least two of the rings A, B and C do not simultaneously represent a benzene ring. ) (In the formula, X ⁷ and X ⁸ represent a hydrogen atom, a lower alkyl group, or a lower alkoxy group.) (In the formula, P represents 0 or 1) More specifically, the diazotization reaction of amines is performed by adding the amines to water containing pyrrolidone or a derivative thereof to obtain a dissolved or slurry state, and then This is carried out by adding a small amount of mineral acid, and then adding nitrite or an aqueous solution thereof while cold or while warming as necessary, and stirring at the same temperature.

Examples of pyrrolidone and pyrrolidone derivatives used in the diazotization reaction of the present invention include N, such as pyrrolidone, N-methylpyrrolidone, N-butylpyrrolidone, N-hydroxyethylpyrrolidone and N-methoxy-propyl-pyrrolidone.
-Alkylpyrrolidone or N-substituted alkylpyrrolidone can be used. Among them, N-methylpyrrolidone and N-hydroxyethylpyrrolidone are preferable because they are easily available. The amount used is selected from the range of 30 to 80% by weight, preferably 40 to 70% by weight, based on the total weight of the medium for the diazotization reaction. If the amount used exceeds this range and is too small, the above amines cannot be sufficiently dissolved and the reaction takes a long time, which is not preferable. On the other hand, if it is too much, the nitrosyl salt produced from nitrite and mineral acid becomes unstable and decomposes,
Alternatively, the dissolution of nitrite becomes insufficient, and the diazotization does not proceed sufficiently, which is disadvantageous.

Examples of the mineral acid include hydrochloric acid, sulfuric acid, and phosphoric acid. Regarding the amount of addition thereof, an amount sufficient to maintain the pH of the reaction solution after addition of nitrite at 2 to 4 is sufficient.

The nitrite is selected from those usually used in this type of reaction, and examples thereof include sodium nitrite and potassium nitrite.

The pH of the reaction solution during the diazotization reaction is preferably in the range of 2-4. When it is lower than this range, the reaction becomes remarkably slow, and when it is higher than this range, byproducts which are considered to be decomposition products of the produced diazonium salt increase, which is not preferable.

The temperature during the diazotization reaction is 10 to 50 ° C, more preferably
15-40 ° C is applied. If the temperature is lower than 10 ° C, the reaction becomes remarkably slow, and if the temperature is higher than 50 ° C, byproducts which are considered to be decomposition products of the produced diazonium salt increase, which is not preferable.

The above formulas [I] and [I
Specific examples of the amines represented by I] and [III] are as follows.

The content of the above-mentioned amines in the reaction solution varies depending on the viscosity of the reaction solution and the strength of the stirring equipment, but is generally in the range of 2 to 20% by weight based on the total weight of the diazotization reaction medium.

The diazonium salt of the amines obtained by the method of the present invention is a coupling component, for example, a naphthol derivative such as H acid, gunker acid, J acid, or an aqueous solution of metaphenylenediamine, metaphenylenediaminesulfonic acid phenol, or the like, A water-soluble dye can be produced by gradually adding and coupling at 5 to 20 ° C. and pH 2 to 10. The water-soluble dye is a dye having excellent water resistance and is useful for an inkjet printer or a stationery.

〔The invention's effect〕

According to the method of the present invention, in the ordinary method of reacting nitrite in a dilute mineral acid, the reaction requires a remarkably long time, or the reaction is not completed, the above-mentioned general formula [I], [II] or [II] The diazotization reaction of amines represented by III] can be carried out in a short time with high conversion and selectivity.

〔Example〕

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 77.9 g of amines represented by the following formula It was added to a mixture of 779 m of water and 779 ml of N-methyl-pyrrolidone, 10 ml of 35% hydrochloric acid was added, and the mixture was stirred at 20 ° C. for 2 hours. Then, 50 ml of water containing 15.9 g of sodium nitrite was added at 20 ° C. Tetrazotization was carried out by stirring at 20 ° C. for 5 hours.

As a result of analysis by high performance liquid chromatography (hereinafter abbreviated as HPLC), the conversion was 98% and the selectivity was 93%.

To the tetrazotization reaction solution, 10 g of sulfamic acid was added to remove the remaining nitrosyl chloride.

A mixed solution containing 22.5 g of metaphenylenediamines in 900 ml of water was added to the tetrazotization reaction solution, and the mixture was added at 10 ° C under a condition of pH 2 to 10
The following dyes were synthesized by a coupling reaction for a period of time.

130 g of sodium chloride was added to the obtained coupling reaction solution for salting out, further filtration was performed, and then washed with 300 ml of 10% saline.

93.1 g (pure amount) of the dye represented by the above structural formula was obtained, which was a theoretical yield of 92%.

As a result of HPLC analysis, the purity of the dye based on the organic substance is 94.
%Met.

 The HPLC analysis was performed under the following conditions.

Analytical instrument LC-5A (Shimadzu) Column Unisil NQ C18 (Gaskuro Industrial Co., Ltd.) Eluent Water / acetonitrile = 50/50 (vol ratio) 0.2% NaH ₂ PO ₄ 0.5% Tetrabutylammonium chloride Sample solution 2000ppm 4μ Comparison Example 1 When the reaction was carried out in the same manner as in Example 1 except that 779 ml of water and 779 ml of N-methyl-pyrrolidone were used instead of 1560 ml of water, the conversion rate was 31%, which was extremely low. The reaction was continued for 24 hours as it was, but the conversion was low at 75% and the selectivity was 81%.

Using this reaction solution, a coupling reaction was carried out in the same manner as in Example 1. As a result, the dye yield was 69% and the purity was 78%, which were low.

Example 2 45.5 g of amines represented by the following formula Add in a mixture of 360 ml of water and 720 ml of pyrrolidone, then
After adding 8 ml of 35% hydrochloric acid and stirring at 15 ° C for 3 hours, 8.4 g of sodium nitrite was added and stirred at pH 4 and 15 ° C for 3 hours to carry out diazotization. As a result of HPLC analysis as in Example 1, the conversion rate was 97% and the selectivity was 95%. 6 g of sulfamic acid was added to this diazotization reaction solution to remove the remaining nitrosyl chloride. In 320 ml of water The diazo solution was added dropwise to a mixed solution containing 31.9 g at 5 ° C. and pH 8 to 10 and the coupling reaction was performed at 5 ° C. and pH 9 for 5 hours.
The following dyes were synthesized.

180 g of sodium chloride was added to the obtained coupling reaction liquid and treated in the same manner as in Example 1 to obtain 76.6 g (pure amount) of the dye of the above structural formula (90% theoretical yield).

 As a result of HPLC analysis, the purity was 98%.

Comparative Example 2 When the reaction was carried out in the same manner as in Example 2 except that 910 ml of water was used instead of 550 ml of water and 360 ml of pyrrolidone, the conversion rate was 13%, which was extremely low. The reaction was continued for 48 hours as it was, but the conversion rate was as low as 39%.

Examples 3 to 5 and Comparative Examples 3 to 5 All of Example 1 and Comparative Example 1 except that the following amines were used instead of the diazo component in Example 1 and Comparative Example 1.
The reaction was carried out in the same manner as in. The results are summarized in the table.

Claims (1)

[Claims] 1. A diazotization reaction for producing a water-soluble dye by diazotizing an amine represented by the following general formula [I], [II] or [III] and then reacting it with a coupling component. Is carried out in an aqueous solution containing 30 to 80% by weight of pyrrolidone or a derivative thereof with respect to the whole medium, and a method for producing a water-soluble dye. (In the formula, X ¹ , X ² , X ³ , X ⁴ and X ⁵ each represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a lower acylamino group or a sulfonic acid group, X represents a sulfonic acid group, and A,
B and C represent a benzene ring. However, at least two of the rings A, B and C do not simultaneously represent a benzene ring. ) (In the formula, X ⁷ and X ⁸ represent a hydrogen atom, a lower alkyl group, or a lower alkoxy group.) (In the formula, P represents 0 or 1)